Neuroscience Letters 617 (2016) 173–177
Contents lists available at ScienceDirect
Neuroscience Letters journal homepage: www.elsevier.com/locate/neulet
Research paper
The impact of childhood maltreatment on redox state: Relationship with oxidative damage and antioxidant defenses in adolescents with no psychiatric disorder Carine Hartmann do Prado a , Rodrigo Grassi-Oliveira b , Andréa Wieck a , Aline Zaparte a , Ledo Daruy Filho b , Maurilio da Silva Morrone c , José C. Moreira c , Moisés Evandro Bauer a,∗ a
Laboratory of Immunosenescence, Institute of Biomedical Research, Pontifical Catholic University of the Rio Grande do Sul (PUCRS), Porto Alegre, Brazil Cognitive Neuroscience Research Group (GNCD), Centre of Studies and Research in Traumatic Stress (NEPTE), Postgraduate Program in Psychology, PUCRS, Porto Alegre, Brazil c Centro de Estudos em estresse Oxidativo, Programa de Pós-graduac¸ão em Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil b
h i g h l i g h t s • Early-life stress (ELS) was associated with increased protein carbonylation. • Adolescents with ELS had higher SOD levels, TRAP kinetics but reduced GPx. • ELS was associated with imbalance in the redox state in healthy adolescents.
a r t i c l e
i n f o
Article history: Received 16 September 2015 Received in revised form 11 December 2015 Accepted 27 January 2016 Available online 1 February 2016 Keywords: Oxidative stress Early life stress Childhood maltreatment Antioxidant biomarkers
a b s t r a c t Early life stress (ELS) has been associated with biological and psychosocial alterations due to developmental reprogramming. Here, we investigated whether childhood maltreatment is associated with an imbalance between the production of oxidative markers and antioxidant defenses. Thirty adolescents with no psychiatric disorder but reporting childhood maltreatment and twenty-seven adolescents with no psychiatric disorder and no history of ELS were recruited for the study. Childhood maltreatment was investigated by the Childhood Trauma Questionnaire (CTQ). Redox state was estimated by plasma levels of protein carbonylation, total thiol content (SH), superoxide dismutase (SOD), glutathione peroxidase (GPx), as well as total reactive antioxidant potential (TRAP). Childhood maltreatment was associated with oxidative stress as shown by increased protein carbonylation. Interestingly, adolescents exposed to maltreatment also displayed higher SOD levels, TRAP kinetics and reduced GPx levels when compared with adolescents who had not undergone childhood maltreatment. No significant differences were observed for SH levels. Taken together, we provide novel evidence indicating that childhood maltreatment is associated with increased oxidative stress markers in otherwise healthy adolescents. © 2016 Elsevier Ireland Ltd. All rights reserved.
1. Introduction In the past 20 years, the impact of childhood maltreatment on children’s mental health has been extensively investigated. Prolonged exposure to early life stress (ELS) can alter the brain
∗ Corresponding author at: Instituto de Pesquisas Biomédicas, Faculty of Biosciences, PUCRS. Av. Ipiranga 6690, 2◦ andar. P.O. Box 1429, Porto Alegre, RS 90.610-000, Brazil. E-mail address: [email protected] (M.E. Bauer). http://dx.doi.org/10.1016/j.neulet.2016.01.062 0304-3940/© 2016 Elsevier Ireland Ltd. All rights reserved.
development, increasing stress-reactivity and vulnerability to depression, post-traumatic stress disorder (PTSD), drug abuse, and schizophrenia [9,15,21–23,26,27]. It has been thought that childhood maltreatment affects neurobiological development, leading to later psychological disorders [12,35]. However, the average time between child abuse exposure and the onset of mental illness is approximately 11.5 years, which means that during adolescence many victims of childhood maltreatment could be asymptomatic or sub-symptomatic, despite the brain going through significant developmental changes [38].
174
C.H. do Prado et al. / Neuroscience Letters 617 (2016) 173–177
Many efforts have been done to attempt to clarify how the brain reacts to ELS, but recently evidence of increased brain oxidative damage has been described following stress [34]. Oxidative stress (OS), including higher production of reactive oxygen and nitrogen species (ROS and RNS), have been extensively implicated in the progression of psychiatric disorders, due to the high vulnerability of brain to increased oxidative load [19,29,31,36]. The imbalance between the production of ROS and engagement of antioxidant defenses in favor of the first is known by oxidative stress [19]. ROS leads to damage, either directly or indirectly, of many biological structures, including lipids, proteins and DNA, causing detrimental effects at both cellular and systemic levels [19,33]. However, at moderate concentrations, ROS and RNS play an important role in physiological processes, as for example in defense against infectious agents, and cellular signaling processes [10,42]. Protein carbonylation and protein thiol modification in plasma are common indexes of oxidative damage [7,44]. Carbonyl groups are formed when protein side chains are oxidized. The accumulation of reactive carbonylated species has been linked to increased cellular toxicity, diseases and psychological stress [11]. Similarly, protein thiol groups are formed through oxidative modifications in protein cysteines and are involved in numerous biological functions [6]. Endogenous antioxidants react with ROS and RNS to protect proteins from carbonylation and thiol modification. Superoxide dismutase (SOD) catalyzes superoxide radicals (• O2 −) into oxygen and hydrogen peroxide (H2 O2 ). Subsequently, peroxides and hydroxyl radicals are metabolized by glutathione peroxidase (GPx) into water and oxygen [13,18]. Therefore, an elevation in SOD/GPx ratio could result in the accumulation of H2 O2 and H2 O2 -derived reactive species such as hydroxyl radicals. If not removed, H2 O2 can contribute to oxidative cellular damage [18,32]. Also, the nonenzymatic antioxidant capacity can be estimated by total reactive antioxidant potential (TRAP) [14]. TRAP measure represents the global non-enzymatic antioxidant capacity of sample that includes active free radicals scavengers such as glutathione, bilirubin, alphatocopherol, ascorbic acid, uric acid and remaining antioxidants [5]. Here, we hypothesize that adolescents exposed to childhood abuse and neglect may have an imbalance of ROS and antioxidant defenses. To the best of our knowledge, this is the first study to investigate the association between ELS and redox dysregulation in adolescents without psychiatric conditions.
severe and over 12 = severe abuse. Sexual abuse severity up to 5 = none or minimal abuse, 6–7 = low to moderate, 8–12 = moderate to severe and over 12 = severe to extreme abuse. Emotional neglect severity up to 9–none or minimal abuse, 10–14 = low to moderate abuse, 15–17 = moderate to severe and over 17 = severe to extreme. Physical neglect severity up to 7 = none or minimal, 8–9 = low to moderate, 10–12 = moderate to severe and over 12 = severe to extreme [4,41]. Childhood Depressive Inventory (CDI) was used to evaluate depressive symptoms and severity [24]. There are 27 items and each item scored on a three-point scale: 0 = absent; 1 = moderate; 2 = severe, classified in order of increasing severity from 0 to 2, which ranges from 0 to 54. A cut-off up to 20 scores indicates the absence of depressive symptoms. Exclusion criteria to both groups were: (a) presence of major axis I disorder such as psychotic disorders, mood disorders, anxiety disorders as well as trauma-related disorders, (b) mental retardation, (c) presence of systemic (hypertension, immune disorders or infection) or neurological diseases, (d) neoplasias, and (e) use of any substance that may induce immune or endocrine changes. Exclusion criteria were determined by interviews and by the Schedule for Affective Disorders and Schizophrenia for School Aged Children—Present and Lifetime Version (K-SADS-PL) and the Wechsler Abbreviated Scale of Intelligence (WASI) inventories [3,43]. This study was approved by the Ethical Committee of Pontifical Catholic University of Rio Grande do Sul (PUCRS), and all subjects provided their written informed consent before inclusion in the study. 2.2. Blood collection and plasma isolation Ten milliliters of peripheral blood were collected by venipuncture and stored in EDTA tubes prior to analyses. Immediately after blood collection, the samples were centrifuged at 1800 rpm for 5 min and the plasma samples were stored at −80 ◦ C until analysis. 2.3. Protein carbonylation Oxidative damage to proteins was measured by quantification of carbonyl groups as previously described [47]. This method is based on the reaction of dinitrophenylhydrazine (DNPH) with protein carbonyl groups. Briefly, proteins were precipitated by the addition of 20% TCA and re-solubilized in DNPH, and absorbance determined by spectrophotometer at 370 nm. Results are expressed in mol carbonyls/mg protein.
2. Methods 2.1. Participants Thirty healthy adolescents between 13 and 17 years old with a history of childhood maltreatment (CM) were recruited by telephone from a database about CM prevalence in students from Porto Alegre, Brazil. From the same database, twenty-seven adolescents without CM history were randomly selected by invitation letters distributed to parents. History of CM was assessed through the validated Portuguese version of Childhood Trauma Questionnaire (CTQ), as reported by Grassi-Oliveira at al., a retrospective 28-item self-report instrument developed to assess childhood maltreatment experiences through 5 subscales: physical abuse, physical neglect, emotional abuse, emotional neglect, and sexual abuse [16]. Each scale is presented in a 5-point Likert-type scale ranging from 5 (no trauma) to 25 (extreme trauma) and the total score is classified from no trauma to extreme trauma according to Bernstein et al. [4]. Briefly, severity of each of the five subscales is scored as the following; emotional abuse 13–15 = moderate to severe and over 15 = severe or extreme. Physical abuse severity up to 7 = none or minimal abuse, 8–9 = low to moderate, 10–12 = moderate to
2.4. Protein thiol content In order to measure the levels of reduced thiol (-SH) groups in protein in serum samples we used the Ellman’s reagent based assay [46]. For this, 60 g sample aliquot was diluted in PBS followed by the addition of 0.01 M 5,5-dithiobis-2-nitrobenzoic acid (DTNB). After 60 min incubation at room temperature, the absorbance was measured in a spectrophotometer set at 412 nm. Results are expressed as mol SH groups/mg protein. 2.5. Antioxidant enzymes activity quantification Superoxide dismutase (SOD) activity was estimated from the inhibition of superoxide anion-dependent adrenaline autooxidation in a spectrophotometer at 480 nm as previously described [50]. Results were expressed as units of SOD/mg protein. Moreover, GPx activity was measured in plasma samples by the rate of NAD(P)H oxidation accessed in a spectrophotometer at 340 nm in the presence of reduced glutathione, tert-butyl hydroperoxide, and glutathione reductase as previously described [51].
C.H. do Prado et al. / Neuroscience Letters 617 (2016) 173–177
2.6. Non enzymatic antioxidant potential (TRAP)
175
TRAP was observed in the childhood maltreatment group (Wald-2 (1) = 8.46; p = 0.004, Fig. 1E).
We used the Total Reactive Antioxidant Potential test (TRAP) as an index of plasma non enzymatic antioxidant potential. This assay is based on the decrease of chemiluminescence produced from the reaction of 2,20-azobis [2-amidinopropane] (AAPH) derived peroxyl radical with luminol due to free radical quenching by the antioxidant compounds present in the sample [48]. Briefly, we prepared AAPH solutions and added luminol (“System” solution, 100% chemiluminescence); thereafter, we waited 2 h for the system to stabilize before performing the first reading. After the addition of the samples, the chemiluminescence was monitored over a 40 min period, the results were transformed to percentages, and the area under curve (AUC) was calculated as previously described [49]. The AUC is inversely proportional to antioxidant capacity, therefore the samples displaying lower AUC will be those with higher antioxidant capacity. 2.7. Statistical analysis All variables were tested for normality of distribution by Shapiro-Wilk tests. For continuous variables, differences between groups were analyzed by Student’s t-test. Qualitative data were analyzed by means of Chi-square. GLM with linear or gamma distribution were performed for each oxidative markers and antioxidant variables according to normality results, using age, sex and BMI as covariates in the model. Statistical analyses were performed using the Statistical Package for Social Sciences, SPSS Statistics 17.0 software (SPSS Inc., Chicago, IL, USA). All data are represented as mean ± SE. We considered error ␣ of 5% and B of 20%. 3. Results 3.1. Characteristics of the studied populations Demographic and clinical characteristics of the study population are presented in Table 1. All groups were homogeneous in age, BMI, sex and income. CTQ scores were statistically different between the two groups, as expected. All statistical data presented here were adjusted for age, sex and BMI. 3.2. Effect of childhood maltreatment on antioxidant defenses As depicted in Fig. 1A, circulating levels of SOD were higher in adolescents exposed to childhood maltreatment (Wald-2 (1) = 114.050; p < 0.001). However, GPx levels displayed a significant reduction when compared to controls (Wald-2 (1) = 11.921; p = 0.001, Fig. 1B). We investigated the SOD/GPx ratio to evaluate susceptibility to oxidative damage. Adolescents exposed to maltreatment showed a higher SOD/GPx ratio (Wald-2 (1) = 19.650; p < 0.001, Fig. 1C). In addition, we identified a significant group effect in the TRAP kinetics (Fig. 1D,E). In particular, a significant decrease in non-enzymatic antioxidant capacity evaluate by
3.3. Effect of childhood maltreatment on protein damage We found significant differences in protein carbonyl levels between groups (Wald-2 (1) = 7.390; p = 0.007, Fig. 2A). Participants reporting a history of childhood maltreatment had increased of carbonyl levels than matched controls. There was no significant differences in the SH levels between groups (Wald-2 (1) = 2.221; p = 0.136, Fig. 2B). 4. Discussion We found that childhood maltreatment is related to alterations in oxidative parameters within adolescents without current psychiatric disorders. Although this work did not establish a causal link between the childhood maltreatment and oxidative stress markers, the data may indicate a pivotal role for ELS in the modulation of biological functions even before the development of psychiatric disorders later in life. ROS and RNS are normally produced in many subcellular structures as part of the metabolism and stress response, having important role in modulating several cellular functions [28]. However, the presence ROS and RNS can be detrimental if endogenous antioxidant mechanisms account for the ROS/RNS. Our data suggests an important imbalance between oxidative molecules/antioxidant defenses in participants who have undergone childhood maltreatment. Specially, we observed an increased SOD/GPX ratio in adolescents exposed to ELS. Stress triggers a set of adaptive physiological and behavioral alterations in order to reestablish homeostasis. Altered hypothalamic-pituitary-adrenal (HPA) axis and immune responses are mobilized following stress exposure and significant overload in these systems are observed following chronic or intense stress, associated with detrimental effects later in life [30]. In our study TRAP results (AUC raw data) were increased in adolescents with history of ELS, suggesting a lower antioxidant capacity in this sample. Interestingly, Tsuber and colleagues demonstrate that exposure to acute stress activates antioxidant defenses, suggesting a beneficial role of acute stress exposure [40]. However, Aschbacher and colleagues demonstrated increased levels of oxidative stress in a group of chronically stress caregivers when exposed to an acutely stressful task, indicating that exposure to previous chronic stress may reduce individual’s oxidative stressed resilience [1]. In both human and animal studies, early life stress has been reported to activate the HPA axis that stimulates adrenal secretion of glucocorticoids. Recent studies have revealed that prolonged exposure to exogenous glucocorticoids can modulate the onset of cellular oxidative stress [37]. Oxidative stress can alter a number of molecular mechanisms including the normal translocation of the glucocorticoid receptors, NMDA receptor up-regulation, modula-
Table 1 Characteristics of the studied populations.
Age years (mean ± SD) Sex Female Male BMI (mean ± SD) CDI (mean ± SD) CTQ Income
Controls
Childhood maltreatment
Statistics
Significance
14.19 ± 1.57
16.47 ± 1.25
t55 = −0.752 2 = 1.113
0.45 0.29
18 9 25.16 ± 3.44 35.25 ± 5.25 28.45 ± 3.52 50.1 ± 9.99
15 15 24.07 ± 2.12 34.20 ± 4.80 42.72 ± 10.57 52.8 ± 10.80
t56 = 1.479 t55 = 0.795 F = 10.03 t44 = 0.469
0.14 0.43 0.003 0.38
Data shown as mean (M) ± standard deviation (SD). Abbreviations: BMI, body mass index. CDI, Childhood Depression Inventory. CTQ, Childhood Trauma Questionnaire.
176
C.H. do Prado et al. / Neuroscience Letters 617 (2016) 173–177
Fig. 1. A) Enzymatic activity of superoxide dismutase (SOD); B) Enzymatic activity of glutathione peroxidase (GPx); C) SOD/GPx ratio between the groups; D) A free-radical (AAPH) generating system produces peroxyl radicals, which are introduced into plasma samples at a constant rate. The effects of antioxidants on free-radical induced chemiluminescence are measured as area under curve; E) The area under curve of total reactive antioxidant potential (arbitrary units). It was assumed an inverse relationship between raw data on the area under the curve and its concentration levels, which means that higher raw data represents a lower antioxidant capacity. Data are shown as mean ± SE. Statistical significant differences are indicated *p < 0.05. (n) = 15 ELS and 15 controls.
Fig. 2. Oxidative stress markers. (A) Protein carbonylation (B) Protein thiol modifications (SH). Data are shown as mean ± SE. Statistical significant group differences are indicated *p < 0.05 and **p < 0.01. (n) = 15 ELS and 15 controls.
tion of kinases and RNA synthesis [34]. It has been shown that children and adolescents with anxiety disorders have altered redox states when compared to healthy subjects, indicating a possible link between pathophysiology of anxiety disorders and oxidative damage [8,17]. In this context, recent evidence indicates that exposure to pre-natal stress leads to higher levels of oxidative damage markers [20,39] and reduced total antioxidant capacity in animal models [39,45]. Additionally, prenatal stress was associated with a decrease in resistance to oxidative damage [45]. Several studies have also shown increases in enzymatic antioxidant activity following overexposure to stress hormones during pre- and post-natal development [2,25]. Taken together, increased TRAP index might be an indicator of impairment of antioxidant defenses in adolescents with history of ELS due to an excess of ROS production or disability of antioxidant defenses. The present study has some limitations. The sample size is relatively small due to the scarcity of adolescents exposed to childhood maltreatment without a history of mood disorders. Future longitudinal studies are needed to further explore the association between childhood maltreatment, oxidative parameters and development of psychiatric disorders later in life.
Our data suggests that exposure to early life stress leads to significant long-lasting biological alterations. We found increased levels of oxidative biomarkers in healthy adolescents following traumatic experiences early in life. In this sense, oxidative stress has been known to enhance the susceptibility of brain tissue to damage, leading to neuroinflammation and neuronal death, indicating a possible comorbid relationship between oxidative biomarkers and development of psychiatric disorders. Conflicts of interest The authors declare no conflict of interest. Acknowledgments This work was supported by grants from CNPq, FAPERGS and CAPES. The funding institutions had no further roles in study design, in the collection, analysis and interpretation of data, in the writing of the report, and in the decision to submit the paper for publication. References
C.H. do Prado et al. / Neuroscience Letters 617 (2016) 173–177 [1] K. Aschbacher, A. O’Donovan, O.M. Wolkowitz, F.S. Dhabhar, Y. Su, E. Epel, Good stress, bad stress and oxidative stress: insights from anticipatory cortisol reactivity, Psychoneuroendocrinology 38 (2013) 1698–1708. [2] S. Atanasova, E. Wieland, C. Schlumbohm, M. Korecka, L. Shaw, N. von Ahsen, E. Fuchs, M. Oellerich, V. Armstrong, Prenatal dexamethasone exposure in the common marmoset monkey enhances gene expression of antioxidant enzymes in the aorta of adult offspring, Stress 12 (2009) 215–224. [3] B.N. Axelrod, Validity of the Wechsler abbreviated scale of intelligence and other very short forms of estimating intellectual functioning, Assessment 9 (2002) 17–23. [4] D.P. Bernstein, J.A. Stein, M.D. Newcomb, E. Walker, D. Pogge, T. Ahluvalia, J. Stokes, L. Handelsman, M. Medrano, D. Desmond, W. Zule, Development and validation of a brief screening version of the Childhood Trauma Questionnaire, Child Abuse Negl. 27 (2003) 169–190. [5] E. Birben, U.M. Sahiner, C. Sackesen, S. Erzurum, O. Kalayci, Oxidative stress and antioxidant defense, World Allergy Org. J. 5 (2012) 9–19. [6] S. Biswas, A.S. Chida, I. Rahman, Redox modifications of protein-thiols: emerging roles in cell signaling, Biochem. Pharmacol. 71 (2006) 551–564. [7] E. Cabiscol, J. Tamarit, J. Ros, Protein carbonylation: proteomics, specificity and relevance to aging, Mass Spectrom. Rev. 33 (2014) 21–48. [8] M.F. Ceylan, E. Guney, M. Alisik, M. Ergin, G.S. Dinc, Z. Goker, S. Eker, M. Kizilgun, O. Erel, Lipid peroxidation markers in children with anxiety disorders and their diagnostic implications, Redox Rep. 19 (2014) 92–96. [9] A. Danese, B.S. McEwen, Adverse childhood experiences, allostasis, allostatic load, and age-related disease, Physiol. Behav. 106 (2012) 29–39. [10] W. Droge, Free radicals in the physiological control of cell function, Physiol. Rev. 82 (2002) 47–95. [11] M. Fedorova, R.C. Bollineni, R. Hoffmann, Protein carbonylation as a major hallmark of oxidative damage: update of analytical strategies, Mass Spectrom. Rev. 33 (2014) 79–97. [12] T. Frodl, V. O’Keane, How does the brain deal with cumulative stress? A review with focus on developmental stress, HPA axis function and hippocampal structure in humans, Neurobiol. Dis. 52 (2013) 24–37. [13] B.I. Frohnert, D.A. Bernlohr, Protein carbonylation, mitochondrial dysfunction, and insulin resistance, Adv. Nutr. 4 (2013) 157–163. [14] A. Ghiselli, M. Serafini, G. Maiani, E. Azzini, A. Ferro-Luzzi, A fluorescence-based method for measuring total plasma antioxidant capability, Free Radic. Biol. Med. 18 (1995) 29–36. [15] R. Grassi-Oliveira, M. Ashy, L.M. Stein, Psychobiology of childhood maltreatment: effects of allostatic load? Rev. Bras. Psiquiatr. 30 (2008) 60–68. [16] R. Grassi-Oliveira, L.M. Stein, J.C. Pezzi, Translation and content validation of the Childhood Trauma Questionnaire into Portuguese language, Rev. Saude Publica 40 (2006) 249–255. [17] E. Guney, M. Fatih Ceylan, A. Tektas, M. Alisik, M. Ergin, Z. Goker, G. Senses Dinc, O. Ozturk, A. Korkmaz, S. Eker, M. Kizilgun, O. Erel, Oxidative stress in children and adolescents with anxiety disorders, J. Affect. Disord. 156 (2014) 62–66. [18] J.M. Gutteridge, B. Halliwell, Free radicals and antioxidants in the year 2000. A historical look to the future, Ann. N. Y. Acad. Sci. 899 (2000) 136–147. [19] B. Halliwell, Oxidative stress and neurodegeneration: where are we now? J. Neurochem. 97 (2006) 1634–1658. [20] M.F. Haussmann, A.S. Longenecker, N.M. Marchetto, S.A. Juliano, R.M. Bowden, Embryonic exposure to corticosterone modifies the juvenile stress response, oxidative stress and telomere length, Proc. Biol. Sci. 279 (2012) 1447–1456. [21] C. Heim, D.J. Newport, R. Bonsall, A.H. Miller, C.B. Nemeroff, Altered pituitary-adrenal axis responses to provocative challenge tests in adult survivors of childhood abuse, Am. J. Psychiatry 158 (2001) 575–581. [22] J.G. Hovens, E.J. Giltay, P. Spinhoven, A.M. van Hemert, B.W. Penninx, Impactof childhood life events and childhood trauma on the onset and recurrence of depressive and anxiety disorders, J. Clin. Psychiatry (2015). [23] P.A. Kelly, E. Viding, G.L. Wallace, M. Schaer, S.A. De Brito, B. Robustelli, E.J. McCrory, Cortical thickness, surface area, and gyrification abnormalities in children exposed to maltreatment: neural markers of vulnerability? Biol. Psychiatry 74 (2013) 845–852. [24] M. Kovacs, The children’s depression, inventory (CDI), Psychopharmacol. Bull. 21 (1985) 995–998. [25] V. Marasco, K.A. Spencer, J. Robinson, P. Herzyk, D. Costantini, Developmental post-natal stress can alter the effects of pre-natal stress on the adult redox balance, Gen. Comp. Endocrinol. 191 (2013) 239–246. [26] E. McCrory, S.A. De Brito, E. Viding, The impact of childhood maltreatment: a review of neurobiological and genetic factors, Front. Psychiatry 2 (2011) 48. [27] M.F. Mello, A.A. Faria, A.F. Mello, L.L. Carpenter, A.R. Tyrka, L.H. Price, Childhood maltreatment and adult psychopathology: pathways to hypothalamic-pituitary-adrenal axis dysfunction, Rev. Bras. Psiquiatr. 31 (Suppl. 2) (2009) S41–48.
177
[28] A. Moniczewski, M. Gawlik, I. Smaga, E. Niedzielska, J. Krzek, E. Przegalinski, J. Pera, M. Filip, Oxidative stress as an etiological factor and a potential treatment target of psychiatric disorders. Part 1. Chemical aspects and biological sources of oxidative stress in the brain, Pharmacol. Rep. 67 (2015) 560–568. [29] F. Ng, M. Berk, O. Dean, A.I. Bush, Oxidative stress in psychiatric disorders: evidence base and therapeutic implications, Int. J. Neuropsychopharmacol. 11 (2008) 851–876. [30] M. Nowacka, E. Obuchowicz, BDNF and VEGF in the pathogenesis of stress-induced affective diseases: an insight from experimental studies, Pharmacol. Rep. 65 (2013) 535–546. [31] C.D. Pandya, K.R. Howell, A. Pillai, Antioxidants as potential therapeutics for neuropsychiatric disorders, Prog. Neuropsychopharmacol. Biol. Psychiatry 46 (2013) 214–223. [32] E.M. Park, N. Ramnath, G.Y. Yang, J.Y. Ahn, Y. Park, T.Y. Lee, H.S. Shin, J. Yu, C. Ip, Y.M. Park, High superoxide dismutase and low glutathione peroxidase activities in red blood cells predict susceptibility of lung cancer patients to radiation pneumonitis, Free Radic. Biol. Med. 42 (2007) 280–287. [33] S. Reuter, S.C. Gupta, M.M. Chaturvedi, B.B. Aggarwal, Oxidative stress, inflammation, and cancer: how are they linked? Free Radic. Biol. Med. 49 (2010) 1603–1616. [34] S. Schiavone, M. Colaianna, L. Curtis, Impact of early life stress on the pathogenesis of mental disorders: relation to brain oxidative stress, Curr. Pharm. Des. 21 (2015) 1404–1412. [35] R.C. Shelton, The molecular neurobiology of depression, Psychiatr. Clin. North Am. 30 (2007) 1–11. [36] M. Siwek, M. Sowa-Kucma, D. Dudek, K. Styczen, B. Szewczyk, K. Kotarska, P. Misztakk, A. Pilc, M. Wolak, G. Nowak, Oxidative stress markers in affective disorders, Pharmacol. Rep. 65 (2013) 1558–1571. [37] J.G. Spiers, H.J. Chen, C. Sernia, N.A. Lavidis, Activation of the hypothalamic-pituitary-adrenal stress axis induces cellular oxidative stress, Front. Neurosci. 8 (2014) 456. [38] M.H. Teicher, J.A. Samson, Childhood maltreatment and psychopathology: a case for ecophenotypic variants as clinically and neurobiologically distinct subtypes, Am. J. Psychiatry 170 (2013) 1114–1133. [39] L.A. Treidel, B.N. Whitley, Z.M. Benowitz-Fredericks, M.F. Haussmann, Prenatal exposure to testosterone impairs oxidative damage repair efficiency in the domestic chicken (Gallus gallus), Biol. Lett. 9 (2013) 20130684. [40] V. Tsuber, Y. Kadamov, L. Tarasenko, Activation of antioxidant defenses in whole saliva by psychosocial stress is more manifested in young women than in young men, PLoS One 9 (2014) e115048. [41] A.M. Tucci, F. Kerr-Correa, M.L.O. Souza-Formigoni, Childhood trauma in substance use disorder and depression: an analysis by gender among a Brazilian Clinical sample, Child Abuse Neglect 34 (2010) 95–104. [42] M. Valko, D. Leibfritz, J. Moncol, M.T. Cronin, M. Mazur, J. Telser, Free radicals and antioxidants in normal physiological functions and human disease, Int. J. Biochem. Cell Biol. 39 (2007) 44–84. [43] D. Wechsler, WASI Manual, Psychological Corporation, San Antonio, TX, 1999. [44] A. Zaparte, T.W. Viola, R. Grassi-Oliveira, M. da Silva Morrone, J.C. Moreira, M.E. Bauer, Early abstinence of crack-cocaine is effective to attenuate oxidative stress and to improve antioxidant defences, Psychopharmacology (Berl.) 232 (2015) 1405–1413. [45] C. Zimmer, K.A. Spencer, Reduced resistance to oxidative stress during reproduction as a cost of early-life stress, Comp. Biochem. Physiol. A Mol. Integr. Physiol. 183 (2015) 9–13. [46] G.L. Ellman, Tissue sulfhydryl groups, Arch. Biochem. Biophys. 82 (1959) 70–77. [47] R.L. Levine, D. Garland, C.N. Oliver, A. Amici, I. Climent, A.G. Lenz, B.W. Ahn, S. Shaltiel, E.R. Stadtman, Determination of carbonyl content in oxidatively modified proteins, Methods Enzymol. 186 (1990) 464–478. [48] E. Lissi, M. Salim-Hanna, C. Pascual, M.D. del Castillo, Evaluation of total antioxidant potential (TRAP) and total antioxidant reactivity from luminol-enhanced chemiluminescence measurements, Free Radical Biol. Med. 18 (1995) 153–158. [49] M.T. Dresch, S.B. Rossato, V.D. Kappel, R. Biegelmeyer, M.L. Hoff, P. Mayorga, J.A. Zuanazzi, A.T. Henriques, J.C. Moreira, Optimization and validation of an alternative method to evaluate total reactive antioxidant potential, Anal. Biochem. 385 (2009) 107–114. [50] H.P. Misra, I. Fridovich, The role of superoxide anion in the autoxidation of epinephrine and a simple assay for superoxide dismutase, J. Biol. Chem. 247 (10) (1972) 3170–3175. ¨ [51] L. Flohe´ı, W.A. Gunzler, Assays of glutathione peroxidase, in: H. Sies (Ed.), Methods in Enzymology, Academic, New York, 1984, pp. 114–121.
Contents lists available at ScienceDirect
Neuroscience Letters journal homepage: www.elsevier.com/locate/neulet
Research paper
The impact of childhood maltreatment on redox state: Relationship with oxidative damage and antioxidant defenses in adolescents with no psychiatric disorder Carine Hartmann do Prado a , Rodrigo Grassi-Oliveira b , Andréa Wieck a , Aline Zaparte a , Ledo Daruy Filho b , Maurilio da Silva Morrone c , José C. Moreira c , Moisés Evandro Bauer a,∗ a
Laboratory of Immunosenescence, Institute of Biomedical Research, Pontifical Catholic University of the Rio Grande do Sul (PUCRS), Porto Alegre, Brazil Cognitive Neuroscience Research Group (GNCD), Centre of Studies and Research in Traumatic Stress (NEPTE), Postgraduate Program in Psychology, PUCRS, Porto Alegre, Brazil c Centro de Estudos em estresse Oxidativo, Programa de Pós-graduac¸ão em Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil b
h i g h l i g h t s • Early-life stress (ELS) was associated with increased protein carbonylation. • Adolescents with ELS had higher SOD levels, TRAP kinetics but reduced GPx. • ELS was associated with imbalance in the redox state in healthy adolescents.
a r t i c l e
i n f o
Article history: Received 16 September 2015 Received in revised form 11 December 2015 Accepted 27 January 2016 Available online 1 February 2016 Keywords: Oxidative stress Early life stress Childhood maltreatment Antioxidant biomarkers
a b s t r a c t Early life stress (ELS) has been associated with biological and psychosocial alterations due to developmental reprogramming. Here, we investigated whether childhood maltreatment is associated with an imbalance between the production of oxidative markers and antioxidant defenses. Thirty adolescents with no psychiatric disorder but reporting childhood maltreatment and twenty-seven adolescents with no psychiatric disorder and no history of ELS were recruited for the study. Childhood maltreatment was investigated by the Childhood Trauma Questionnaire (CTQ). Redox state was estimated by plasma levels of protein carbonylation, total thiol content (SH), superoxide dismutase (SOD), glutathione peroxidase (GPx), as well as total reactive antioxidant potential (TRAP). Childhood maltreatment was associated with oxidative stress as shown by increased protein carbonylation. Interestingly, adolescents exposed to maltreatment also displayed higher SOD levels, TRAP kinetics and reduced GPx levels when compared with adolescents who had not undergone childhood maltreatment. No significant differences were observed for SH levels. Taken together, we provide novel evidence indicating that childhood maltreatment is associated with increased oxidative stress markers in otherwise healthy adolescents. © 2016 Elsevier Ireland Ltd. All rights reserved.
1. Introduction In the past 20 years, the impact of childhood maltreatment on children’s mental health has been extensively investigated. Prolonged exposure to early life stress (ELS) can alter the brain
∗ Corresponding author at: Instituto de Pesquisas Biomédicas, Faculty of Biosciences, PUCRS. Av. Ipiranga 6690, 2◦ andar. P.O. Box 1429, Porto Alegre, RS 90.610-000, Brazil. E-mail address: [email protected] (M.E. Bauer). http://dx.doi.org/10.1016/j.neulet.2016.01.062 0304-3940/© 2016 Elsevier Ireland Ltd. All rights reserved.
development, increasing stress-reactivity and vulnerability to depression, post-traumatic stress disorder (PTSD), drug abuse, and schizophrenia [9,15,21–23,26,27]. It has been thought that childhood maltreatment affects neurobiological development, leading to later psychological disorders [12,35]. However, the average time between child abuse exposure and the onset of mental illness is approximately 11.5 years, which means that during adolescence many victims of childhood maltreatment could be asymptomatic or sub-symptomatic, despite the brain going through significant developmental changes [38].
174
C.H. do Prado et al. / Neuroscience Letters 617 (2016) 173–177
Many efforts have been done to attempt to clarify how the brain reacts to ELS, but recently evidence of increased brain oxidative damage has been described following stress [34]. Oxidative stress (OS), including higher production of reactive oxygen and nitrogen species (ROS and RNS), have been extensively implicated in the progression of psychiatric disorders, due to the high vulnerability of brain to increased oxidative load [19,29,31,36]. The imbalance between the production of ROS and engagement of antioxidant defenses in favor of the first is known by oxidative stress [19]. ROS leads to damage, either directly or indirectly, of many biological structures, including lipids, proteins and DNA, causing detrimental effects at both cellular and systemic levels [19,33]. However, at moderate concentrations, ROS and RNS play an important role in physiological processes, as for example in defense against infectious agents, and cellular signaling processes [10,42]. Protein carbonylation and protein thiol modification in plasma are common indexes of oxidative damage [7,44]. Carbonyl groups are formed when protein side chains are oxidized. The accumulation of reactive carbonylated species has been linked to increased cellular toxicity, diseases and psychological stress [11]. Similarly, protein thiol groups are formed through oxidative modifications in protein cysteines and are involved in numerous biological functions [6]. Endogenous antioxidants react with ROS and RNS to protect proteins from carbonylation and thiol modification. Superoxide dismutase (SOD) catalyzes superoxide radicals (• O2 −) into oxygen and hydrogen peroxide (H2 O2 ). Subsequently, peroxides and hydroxyl radicals are metabolized by glutathione peroxidase (GPx) into water and oxygen [13,18]. Therefore, an elevation in SOD/GPx ratio could result in the accumulation of H2 O2 and H2 O2 -derived reactive species such as hydroxyl radicals. If not removed, H2 O2 can contribute to oxidative cellular damage [18,32]. Also, the nonenzymatic antioxidant capacity can be estimated by total reactive antioxidant potential (TRAP) [14]. TRAP measure represents the global non-enzymatic antioxidant capacity of sample that includes active free radicals scavengers such as glutathione, bilirubin, alphatocopherol, ascorbic acid, uric acid and remaining antioxidants [5]. Here, we hypothesize that adolescents exposed to childhood abuse and neglect may have an imbalance of ROS and antioxidant defenses. To the best of our knowledge, this is the first study to investigate the association between ELS and redox dysregulation in adolescents without psychiatric conditions.
severe and over 12 = severe abuse. Sexual abuse severity up to 5 = none or minimal abuse, 6–7 = low to moderate, 8–12 = moderate to severe and over 12 = severe to extreme abuse. Emotional neglect severity up to 9–none or minimal abuse, 10–14 = low to moderate abuse, 15–17 = moderate to severe and over 17 = severe to extreme. Physical neglect severity up to 7 = none or minimal, 8–9 = low to moderate, 10–12 = moderate to severe and over 12 = severe to extreme [4,41]. Childhood Depressive Inventory (CDI) was used to evaluate depressive symptoms and severity [24]. There are 27 items and each item scored on a three-point scale: 0 = absent; 1 = moderate; 2 = severe, classified in order of increasing severity from 0 to 2, which ranges from 0 to 54. A cut-off up to 20 scores indicates the absence of depressive symptoms. Exclusion criteria to both groups were: (a) presence of major axis I disorder such as psychotic disorders, mood disorders, anxiety disorders as well as trauma-related disorders, (b) mental retardation, (c) presence of systemic (hypertension, immune disorders or infection) or neurological diseases, (d) neoplasias, and (e) use of any substance that may induce immune or endocrine changes. Exclusion criteria were determined by interviews and by the Schedule for Affective Disorders and Schizophrenia for School Aged Children—Present and Lifetime Version (K-SADS-PL) and the Wechsler Abbreviated Scale of Intelligence (WASI) inventories [3,43]. This study was approved by the Ethical Committee of Pontifical Catholic University of Rio Grande do Sul (PUCRS), and all subjects provided their written informed consent before inclusion in the study. 2.2. Blood collection and plasma isolation Ten milliliters of peripheral blood were collected by venipuncture and stored in EDTA tubes prior to analyses. Immediately after blood collection, the samples were centrifuged at 1800 rpm for 5 min and the plasma samples were stored at −80 ◦ C until analysis. 2.3. Protein carbonylation Oxidative damage to proteins was measured by quantification of carbonyl groups as previously described [47]. This method is based on the reaction of dinitrophenylhydrazine (DNPH) with protein carbonyl groups. Briefly, proteins were precipitated by the addition of 20% TCA and re-solubilized in DNPH, and absorbance determined by spectrophotometer at 370 nm. Results are expressed in mol carbonyls/mg protein.
2. Methods 2.1. Participants Thirty healthy adolescents between 13 and 17 years old with a history of childhood maltreatment (CM) were recruited by telephone from a database about CM prevalence in students from Porto Alegre, Brazil. From the same database, twenty-seven adolescents without CM history were randomly selected by invitation letters distributed to parents. History of CM was assessed through the validated Portuguese version of Childhood Trauma Questionnaire (CTQ), as reported by Grassi-Oliveira at al., a retrospective 28-item self-report instrument developed to assess childhood maltreatment experiences through 5 subscales: physical abuse, physical neglect, emotional abuse, emotional neglect, and sexual abuse [16]. Each scale is presented in a 5-point Likert-type scale ranging from 5 (no trauma) to 25 (extreme trauma) and the total score is classified from no trauma to extreme trauma according to Bernstein et al. [4]. Briefly, severity of each of the five subscales is scored as the following; emotional abuse 13–15 = moderate to severe and over 15 = severe or extreme. Physical abuse severity up to 7 = none or minimal abuse, 8–9 = low to moderate, 10–12 = moderate to
2.4. Protein thiol content In order to measure the levels of reduced thiol (-SH) groups in protein in serum samples we used the Ellman’s reagent based assay [46]. For this, 60 g sample aliquot was diluted in PBS followed by the addition of 0.01 M 5,5-dithiobis-2-nitrobenzoic acid (DTNB). After 60 min incubation at room temperature, the absorbance was measured in a spectrophotometer set at 412 nm. Results are expressed as mol SH groups/mg protein. 2.5. Antioxidant enzymes activity quantification Superoxide dismutase (SOD) activity was estimated from the inhibition of superoxide anion-dependent adrenaline autooxidation in a spectrophotometer at 480 nm as previously described [50]. Results were expressed as units of SOD/mg protein. Moreover, GPx activity was measured in plasma samples by the rate of NAD(P)H oxidation accessed in a spectrophotometer at 340 nm in the presence of reduced glutathione, tert-butyl hydroperoxide, and glutathione reductase as previously described [51].
C.H. do Prado et al. / Neuroscience Letters 617 (2016) 173–177
2.6. Non enzymatic antioxidant potential (TRAP)
175
TRAP was observed in the childhood maltreatment group (Wald-2 (1) = 8.46; p = 0.004, Fig. 1E).
We used the Total Reactive Antioxidant Potential test (TRAP) as an index of plasma non enzymatic antioxidant potential. This assay is based on the decrease of chemiluminescence produced from the reaction of 2,20-azobis [2-amidinopropane] (AAPH) derived peroxyl radical with luminol due to free radical quenching by the antioxidant compounds present in the sample [48]. Briefly, we prepared AAPH solutions and added luminol (“System” solution, 100% chemiluminescence); thereafter, we waited 2 h for the system to stabilize before performing the first reading. After the addition of the samples, the chemiluminescence was monitored over a 40 min period, the results were transformed to percentages, and the area under curve (AUC) was calculated as previously described [49]. The AUC is inversely proportional to antioxidant capacity, therefore the samples displaying lower AUC will be those with higher antioxidant capacity. 2.7. Statistical analysis All variables were tested for normality of distribution by Shapiro-Wilk tests. For continuous variables, differences between groups were analyzed by Student’s t-test. Qualitative data were analyzed by means of Chi-square. GLM with linear or gamma distribution were performed for each oxidative markers and antioxidant variables according to normality results, using age, sex and BMI as covariates in the model. Statistical analyses were performed using the Statistical Package for Social Sciences, SPSS Statistics 17.0 software (SPSS Inc., Chicago, IL, USA). All data are represented as mean ± SE. We considered error ␣ of 5% and B of 20%. 3. Results 3.1. Characteristics of the studied populations Demographic and clinical characteristics of the study population are presented in Table 1. All groups were homogeneous in age, BMI, sex and income. CTQ scores were statistically different between the two groups, as expected. All statistical data presented here were adjusted for age, sex and BMI. 3.2. Effect of childhood maltreatment on antioxidant defenses As depicted in Fig. 1A, circulating levels of SOD were higher in adolescents exposed to childhood maltreatment (Wald-2 (1) = 114.050; p < 0.001). However, GPx levels displayed a significant reduction when compared to controls (Wald-2 (1) = 11.921; p = 0.001, Fig. 1B). We investigated the SOD/GPx ratio to evaluate susceptibility to oxidative damage. Adolescents exposed to maltreatment showed a higher SOD/GPx ratio (Wald-2 (1) = 19.650; p < 0.001, Fig. 1C). In addition, we identified a significant group effect in the TRAP kinetics (Fig. 1D,E). In particular, a significant decrease in non-enzymatic antioxidant capacity evaluate by
3.3. Effect of childhood maltreatment on protein damage We found significant differences in protein carbonyl levels between groups (Wald-2 (1) = 7.390; p = 0.007, Fig. 2A). Participants reporting a history of childhood maltreatment had increased of carbonyl levels than matched controls. There was no significant differences in the SH levels between groups (Wald-2 (1) = 2.221; p = 0.136, Fig. 2B). 4. Discussion We found that childhood maltreatment is related to alterations in oxidative parameters within adolescents without current psychiatric disorders. Although this work did not establish a causal link between the childhood maltreatment and oxidative stress markers, the data may indicate a pivotal role for ELS in the modulation of biological functions even before the development of psychiatric disorders later in life. ROS and RNS are normally produced in many subcellular structures as part of the metabolism and stress response, having important role in modulating several cellular functions [28]. However, the presence ROS and RNS can be detrimental if endogenous antioxidant mechanisms account for the ROS/RNS. Our data suggests an important imbalance between oxidative molecules/antioxidant defenses in participants who have undergone childhood maltreatment. Specially, we observed an increased SOD/GPX ratio in adolescents exposed to ELS. Stress triggers a set of adaptive physiological and behavioral alterations in order to reestablish homeostasis. Altered hypothalamic-pituitary-adrenal (HPA) axis and immune responses are mobilized following stress exposure and significant overload in these systems are observed following chronic or intense stress, associated with detrimental effects later in life [30]. In our study TRAP results (AUC raw data) were increased in adolescents with history of ELS, suggesting a lower antioxidant capacity in this sample. Interestingly, Tsuber and colleagues demonstrate that exposure to acute stress activates antioxidant defenses, suggesting a beneficial role of acute stress exposure [40]. However, Aschbacher and colleagues demonstrated increased levels of oxidative stress in a group of chronically stress caregivers when exposed to an acutely stressful task, indicating that exposure to previous chronic stress may reduce individual’s oxidative stressed resilience [1]. In both human and animal studies, early life stress has been reported to activate the HPA axis that stimulates adrenal secretion of glucocorticoids. Recent studies have revealed that prolonged exposure to exogenous glucocorticoids can modulate the onset of cellular oxidative stress [37]. Oxidative stress can alter a number of molecular mechanisms including the normal translocation of the glucocorticoid receptors, NMDA receptor up-regulation, modula-
Table 1 Characteristics of the studied populations.
Age years (mean ± SD) Sex Female Male BMI (mean ± SD) CDI (mean ± SD) CTQ Income
Controls
Childhood maltreatment
Statistics
Significance
14.19 ± 1.57
16.47 ± 1.25
t55 = −0.752 2 = 1.113
0.45 0.29
18 9 25.16 ± 3.44 35.25 ± 5.25 28.45 ± 3.52 50.1 ± 9.99
15 15 24.07 ± 2.12 34.20 ± 4.80 42.72 ± 10.57 52.8 ± 10.80
t56 = 1.479 t55 = 0.795 F = 10.03 t44 = 0.469
0.14 0.43 0.003 0.38
Data shown as mean (M) ± standard deviation (SD). Abbreviations: BMI, body mass index. CDI, Childhood Depression Inventory. CTQ, Childhood Trauma Questionnaire.
176
C.H. do Prado et al. / Neuroscience Letters 617 (2016) 173–177
Fig. 1. A) Enzymatic activity of superoxide dismutase (SOD); B) Enzymatic activity of glutathione peroxidase (GPx); C) SOD/GPx ratio between the groups; D) A free-radical (AAPH) generating system produces peroxyl radicals, which are introduced into plasma samples at a constant rate. The effects of antioxidants on free-radical induced chemiluminescence are measured as area under curve; E) The area under curve of total reactive antioxidant potential (arbitrary units). It was assumed an inverse relationship between raw data on the area under the curve and its concentration levels, which means that higher raw data represents a lower antioxidant capacity. Data are shown as mean ± SE. Statistical significant differences are indicated *p < 0.05. (n) = 15 ELS and 15 controls.
Fig. 2. Oxidative stress markers. (A) Protein carbonylation (B) Protein thiol modifications (SH). Data are shown as mean ± SE. Statistical significant group differences are indicated *p < 0.05 and **p < 0.01. (n) = 15 ELS and 15 controls.
tion of kinases and RNA synthesis [34]. It has been shown that children and adolescents with anxiety disorders have altered redox states when compared to healthy subjects, indicating a possible link between pathophysiology of anxiety disorders and oxidative damage [8,17]. In this context, recent evidence indicates that exposure to pre-natal stress leads to higher levels of oxidative damage markers [20,39] and reduced total antioxidant capacity in animal models [39,45]. Additionally, prenatal stress was associated with a decrease in resistance to oxidative damage [45]. Several studies have also shown increases in enzymatic antioxidant activity following overexposure to stress hormones during pre- and post-natal development [2,25]. Taken together, increased TRAP index might be an indicator of impairment of antioxidant defenses in adolescents with history of ELS due to an excess of ROS production or disability of antioxidant defenses. The present study has some limitations. The sample size is relatively small due to the scarcity of adolescents exposed to childhood maltreatment without a history of mood disorders. Future longitudinal studies are needed to further explore the association between childhood maltreatment, oxidative parameters and development of psychiatric disorders later in life.
Our data suggests that exposure to early life stress leads to significant long-lasting biological alterations. We found increased levels of oxidative biomarkers in healthy adolescents following traumatic experiences early in life. In this sense, oxidative stress has been known to enhance the susceptibility of brain tissue to damage, leading to neuroinflammation and neuronal death, indicating a possible comorbid relationship between oxidative biomarkers and development of psychiatric disorders. Conflicts of interest The authors declare no conflict of interest. Acknowledgments This work was supported by grants from CNPq, FAPERGS and CAPES. The funding institutions had no further roles in study design, in the collection, analysis and interpretation of data, in the writing of the report, and in the decision to submit the paper for publication. References
C.H. do Prado et al. / Neuroscience Letters 617 (2016) 173–177 [1] K. Aschbacher, A. O’Donovan, O.M. Wolkowitz, F.S. Dhabhar, Y. Su, E. Epel, Good stress, bad stress and oxidative stress: insights from anticipatory cortisol reactivity, Psychoneuroendocrinology 38 (2013) 1698–1708. [2] S. Atanasova, E. Wieland, C. Schlumbohm, M. Korecka, L. Shaw, N. von Ahsen, E. Fuchs, M. Oellerich, V. Armstrong, Prenatal dexamethasone exposure in the common marmoset monkey enhances gene expression of antioxidant enzymes in the aorta of adult offspring, Stress 12 (2009) 215–224. [3] B.N. Axelrod, Validity of the Wechsler abbreviated scale of intelligence and other very short forms of estimating intellectual functioning, Assessment 9 (2002) 17–23. [4] D.P. Bernstein, J.A. Stein, M.D. Newcomb, E. Walker, D. Pogge, T. Ahluvalia, J. Stokes, L. Handelsman, M. Medrano, D. Desmond, W. Zule, Development and validation of a brief screening version of the Childhood Trauma Questionnaire, Child Abuse Negl. 27 (2003) 169–190. [5] E. Birben, U.M. Sahiner, C. Sackesen, S. Erzurum, O. Kalayci, Oxidative stress and antioxidant defense, World Allergy Org. J. 5 (2012) 9–19. [6] S. Biswas, A.S. Chida, I. Rahman, Redox modifications of protein-thiols: emerging roles in cell signaling, Biochem. Pharmacol. 71 (2006) 551–564. [7] E. Cabiscol, J. Tamarit, J. Ros, Protein carbonylation: proteomics, specificity and relevance to aging, Mass Spectrom. Rev. 33 (2014) 21–48. [8] M.F. Ceylan, E. Guney, M. Alisik, M. Ergin, G.S. Dinc, Z. Goker, S. Eker, M. Kizilgun, O. Erel, Lipid peroxidation markers in children with anxiety disorders and their diagnostic implications, Redox Rep. 19 (2014) 92–96. [9] A. Danese, B.S. McEwen, Adverse childhood experiences, allostasis, allostatic load, and age-related disease, Physiol. Behav. 106 (2012) 29–39. [10] W. Droge, Free radicals in the physiological control of cell function, Physiol. Rev. 82 (2002) 47–95. [11] M. Fedorova, R.C. Bollineni, R. Hoffmann, Protein carbonylation as a major hallmark of oxidative damage: update of analytical strategies, Mass Spectrom. Rev. 33 (2014) 79–97. [12] T. Frodl, V. O’Keane, How does the brain deal with cumulative stress? A review with focus on developmental stress, HPA axis function and hippocampal structure in humans, Neurobiol. Dis. 52 (2013) 24–37. [13] B.I. Frohnert, D.A. Bernlohr, Protein carbonylation, mitochondrial dysfunction, and insulin resistance, Adv. Nutr. 4 (2013) 157–163. [14] A. Ghiselli, M. Serafini, G. Maiani, E. Azzini, A. Ferro-Luzzi, A fluorescence-based method for measuring total plasma antioxidant capability, Free Radic. Biol. Med. 18 (1995) 29–36. [15] R. Grassi-Oliveira, M. Ashy, L.M. Stein, Psychobiology of childhood maltreatment: effects of allostatic load? Rev. Bras. Psiquiatr. 30 (2008) 60–68. [16] R. Grassi-Oliveira, L.M. Stein, J.C. Pezzi, Translation and content validation of the Childhood Trauma Questionnaire into Portuguese language, Rev. Saude Publica 40 (2006) 249–255. [17] E. Guney, M. Fatih Ceylan, A. Tektas, M. Alisik, M. Ergin, Z. Goker, G. Senses Dinc, O. Ozturk, A. Korkmaz, S. Eker, M. Kizilgun, O. Erel, Oxidative stress in children and adolescents with anxiety disorders, J. Affect. Disord. 156 (2014) 62–66. [18] J.M. Gutteridge, B. Halliwell, Free radicals and antioxidants in the year 2000. A historical look to the future, Ann. N. Y. Acad. Sci. 899 (2000) 136–147. [19] B. Halliwell, Oxidative stress and neurodegeneration: where are we now? J. Neurochem. 97 (2006) 1634–1658. [20] M.F. Haussmann, A.S. Longenecker, N.M. Marchetto, S.A. Juliano, R.M. Bowden, Embryonic exposure to corticosterone modifies the juvenile stress response, oxidative stress and telomere length, Proc. Biol. Sci. 279 (2012) 1447–1456. [21] C. Heim, D.J. Newport, R. Bonsall, A.H. Miller, C.B. Nemeroff, Altered pituitary-adrenal axis responses to provocative challenge tests in adult survivors of childhood abuse, Am. J. Psychiatry 158 (2001) 575–581. [22] J.G. Hovens, E.J. Giltay, P. Spinhoven, A.M. van Hemert, B.W. Penninx, Impactof childhood life events and childhood trauma on the onset and recurrence of depressive and anxiety disorders, J. Clin. Psychiatry (2015). [23] P.A. Kelly, E. Viding, G.L. Wallace, M. Schaer, S.A. De Brito, B. Robustelli, E.J. McCrory, Cortical thickness, surface area, and gyrification abnormalities in children exposed to maltreatment: neural markers of vulnerability? Biol. Psychiatry 74 (2013) 845–852. [24] M. Kovacs, The children’s depression, inventory (CDI), Psychopharmacol. Bull. 21 (1985) 995–998. [25] V. Marasco, K.A. Spencer, J. Robinson, P. Herzyk, D. Costantini, Developmental post-natal stress can alter the effects of pre-natal stress on the adult redox balance, Gen. Comp. Endocrinol. 191 (2013) 239–246. [26] E. McCrory, S.A. De Brito, E. Viding, The impact of childhood maltreatment: a review of neurobiological and genetic factors, Front. Psychiatry 2 (2011) 48. [27] M.F. Mello, A.A. Faria, A.F. Mello, L.L. Carpenter, A.R. Tyrka, L.H. Price, Childhood maltreatment and adult psychopathology: pathways to hypothalamic-pituitary-adrenal axis dysfunction, Rev. Bras. Psiquiatr. 31 (Suppl. 2) (2009) S41–48.
177
[28] A. Moniczewski, M. Gawlik, I. Smaga, E. Niedzielska, J. Krzek, E. Przegalinski, J. Pera, M. Filip, Oxidative stress as an etiological factor and a potential treatment target of psychiatric disorders. Part 1. Chemical aspects and biological sources of oxidative stress in the brain, Pharmacol. Rep. 67 (2015) 560–568. [29] F. Ng, M. Berk, O. Dean, A.I. Bush, Oxidative stress in psychiatric disorders: evidence base and therapeutic implications, Int. J. Neuropsychopharmacol. 11 (2008) 851–876. [30] M. Nowacka, E. Obuchowicz, BDNF and VEGF in the pathogenesis of stress-induced affective diseases: an insight from experimental studies, Pharmacol. Rep. 65 (2013) 535–546. [31] C.D. Pandya, K.R. Howell, A. Pillai, Antioxidants as potential therapeutics for neuropsychiatric disorders, Prog. Neuropsychopharmacol. Biol. Psychiatry 46 (2013) 214–223. [32] E.M. Park, N. Ramnath, G.Y. Yang, J.Y. Ahn, Y. Park, T.Y. Lee, H.S. Shin, J. Yu, C. Ip, Y.M. Park, High superoxide dismutase and low glutathione peroxidase activities in red blood cells predict susceptibility of lung cancer patients to radiation pneumonitis, Free Radic. Biol. Med. 42 (2007) 280–287. [33] S. Reuter, S.C. Gupta, M.M. Chaturvedi, B.B. Aggarwal, Oxidative stress, inflammation, and cancer: how are they linked? Free Radic. Biol. Med. 49 (2010) 1603–1616. [34] S. Schiavone, M. Colaianna, L. Curtis, Impact of early life stress on the pathogenesis of mental disorders: relation to brain oxidative stress, Curr. Pharm. Des. 21 (2015) 1404–1412. [35] R.C. Shelton, The molecular neurobiology of depression, Psychiatr. Clin. North Am. 30 (2007) 1–11. [36] M. Siwek, M. Sowa-Kucma, D. Dudek, K. Styczen, B. Szewczyk, K. Kotarska, P. Misztakk, A. Pilc, M. Wolak, G. Nowak, Oxidative stress markers in affective disorders, Pharmacol. Rep. 65 (2013) 1558–1571. [37] J.G. Spiers, H.J. Chen, C. Sernia, N.A. Lavidis, Activation of the hypothalamic-pituitary-adrenal stress axis induces cellular oxidative stress, Front. Neurosci. 8 (2014) 456. [38] M.H. Teicher, J.A. Samson, Childhood maltreatment and psychopathology: a case for ecophenotypic variants as clinically and neurobiologically distinct subtypes, Am. J. Psychiatry 170 (2013) 1114–1133. [39] L.A. Treidel, B.N. Whitley, Z.M. Benowitz-Fredericks, M.F. Haussmann, Prenatal exposure to testosterone impairs oxidative damage repair efficiency in the domestic chicken (Gallus gallus), Biol. Lett. 9 (2013) 20130684. [40] V. Tsuber, Y. Kadamov, L. Tarasenko, Activation of antioxidant defenses in whole saliva by psychosocial stress is more manifested in young women than in young men, PLoS One 9 (2014) e115048. [41] A.M. Tucci, F. Kerr-Correa, M.L.O. Souza-Formigoni, Childhood trauma in substance use disorder and depression: an analysis by gender among a Brazilian Clinical sample, Child Abuse Neglect 34 (2010) 95–104. [42] M. Valko, D. Leibfritz, J. Moncol, M.T. Cronin, M. Mazur, J. Telser, Free radicals and antioxidants in normal physiological functions and human disease, Int. J. Biochem. Cell Biol. 39 (2007) 44–84. [43] D. Wechsler, WASI Manual, Psychological Corporation, San Antonio, TX, 1999. [44] A. Zaparte, T.W. Viola, R. Grassi-Oliveira, M. da Silva Morrone, J.C. Moreira, M.E. Bauer, Early abstinence of crack-cocaine is effective to attenuate oxidative stress and to improve antioxidant defences, Psychopharmacology (Berl.) 232 (2015) 1405–1413. [45] C. Zimmer, K.A. Spencer, Reduced resistance to oxidative stress during reproduction as a cost of early-life stress, Comp. Biochem. Physiol. A Mol. Integr. Physiol. 183 (2015) 9–13. [46] G.L. Ellman, Tissue sulfhydryl groups, Arch. Biochem. Biophys. 82 (1959) 70–77. [47] R.L. Levine, D. Garland, C.N. Oliver, A. Amici, I. Climent, A.G. Lenz, B.W. Ahn, S. Shaltiel, E.R. Stadtman, Determination of carbonyl content in oxidatively modified proteins, Methods Enzymol. 186 (1990) 464–478. [48] E. Lissi, M. Salim-Hanna, C. Pascual, M.D. del Castillo, Evaluation of total antioxidant potential (TRAP) and total antioxidant reactivity from luminol-enhanced chemiluminescence measurements, Free Radical Biol. Med. 18 (1995) 153–158. [49] M.T. Dresch, S.B. Rossato, V.D. Kappel, R. Biegelmeyer, M.L. Hoff, P. Mayorga, J.A. Zuanazzi, A.T. Henriques, J.C. Moreira, Optimization and validation of an alternative method to evaluate total reactive antioxidant potential, Anal. Biochem. 385 (2009) 107–114. [50] H.P. Misra, I. Fridovich, The role of superoxide anion in the autoxidation of epinephrine and a simple assay for superoxide dismutase, J. Biol. Chem. 247 (10) (1972) 3170–3175. ¨ [51] L. Flohe´ı, W.A. Gunzler, Assays of glutathione peroxidase, in: H. Sies (Ed.), Methods in Enzymology, Academic, New York, 1984, pp. 114–121.
